A flat panel display has the advantages of being small, lightweight, low in power consumption, and so forth, and therefore the flat panel display has already replaced the Cathode Ray Tube, or CRT, to become the trend of a new generation of displays. However, along with the increasingly mature development of flat panel display technologies, users have increasingly higher requirements for the display quality of flat panel displays, in addition to the size, weight, and so forth, and the display quality of flat panel displays is highly related to the design of their pixel structures.
Generally speaking, a pixel structure includes an active element, a pixel electrode, and a storage capacitor. The active element is used as a switch component of the pixel structure. The pixel electrode is used for providing operation voltage for driving a display medium. The storage capacitor is used for holding the operation voltage of the pixel electrode. If the storage capacitance of the storage capacitor is insufficient, the operation voltage of the pixel electrode cannot be maintained till the next time the active element is started. In this case, abnormal display may be caused by the condition that the operation voltage of the pixel electrode is lower than a predetermined value. Therefore, in order to maintain a certain display quality, the storage capacitor in the pixel structure must have a sufficient capacitance value to ensure maintenance of the operation voltage.
One technical method which ensures the storage capacitor to have a sufficient capacitance value is to provide an electrode of the storage capacitor having sufficient area. However, the electrode of the storage capacitor is generally made of non-transparent materials, and when the area of the electrode of the storage capacitor increases, the aperture ratio of the pixel electrode becomes smaller. Thus, the display quality is deteriorated due to the insufficient brightness of the flat panel display. Therefore, one of the problems to be solved is to effectively increase the capacitance value of the storage capacitor while maintaining a good aperture ratio of the pixel electrode.